Test USB para el stm32

testUSB.ino

#include <USBComposite.h>
USBCompositeSerial CompositeSerial;

void setup() 
{
  CompositeSerial.registerComponent();
  USBComposite.begin();
  delay(2000);
}

void loop() 
{
  CompositeSerial.println("Hello World!");
  delay(500);
}